package com.huixin.zhang.common.utils;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Md5Encrypt {
	private static final char[] DIGITS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e',
			'f' };

	public static String md5(String text, String charset) {
		MessageDigest msgDigest = null;
		try {
			msgDigest = MessageDigest.getInstance("MD5");
		} catch (NoSuchAlgorithmException e) {
			throw new IllegalStateException("System doesn't support MD5 algorithm.");
		}

		try {
			msgDigest.update(text.getBytes(charset));
		} catch (UnsupportedEncodingException e) {
			throw new IllegalStateException("System doesn't support your  EncodingException.");
		}

		byte[] bytes = msgDigest.digest();

		String md5Str = new String(encodeHex(bytes));

		return md5Str;
	}

	public static char[] encodeHex(byte[] data) {
		int l = data.length;
		char[] out = new char[l << 1];
		int i = 0;
		for (int j = 0; i < l; i++) {
			out[(j++)] = DIGITS[((0xF0 & data[i]) >>> 4)];
			out[(j++)] = DIGITS[(0xF & data[i])];
		}
		return out;
	}

	/**
	 * md5 加密
	 * @param src 需的加密字符串
	 * @return
	 */
	public static String getMd5(String src){
		MessageDigest md5 = null;
		try {
			// 参数代表的是算法名称
			md5 = MessageDigest.getInstance("md5");
			byte[] result = md5.digest(src.getBytes());

			StringBuilder sb = new StringBuilder(32);
			// 将结果转为16进制字符  0~9 A~F
			for (int i = 0; i < result.length; i++) {
				// 一个字节对应两个字符
				byte x = result[i];
				// 取得高位
				int h = 0x0f & (x >>> 4);
				// 取得低位
				int l = 0x0f & x;
				sb.append(DIGITS[h]).append(DIGITS[l]);
			}
			return sb.toString();

		} catch (NoSuchAlgorithmException e) {
			throw new RuntimeException(e);
		}
	}
}